Anti rotation bead

ABSTRACT

Sheet metal lid for closing can body, in which lid includes a panel and surrounding seamable edge suitable for attaching to can body. An openable area is defined on panel by a weakening line, and tab is disposed on a mounting place outside openable area. Tab has grip portion, opening portion, and attaching portion, such that attaching portion is provided for attaching tab substantially parallel with respect to panel, and tab is attached so that it is disposed with its opening portion above openable area. Near to at least one edge of attaching portion, at least one strip-shaped projection is shaped to protrude out of panel for limiting a pivoting movement (α) of tab around mounting place. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the provision of a positional fixing of a tabon a sheet metal lid for attaching to a body of a beverage can.

2. Discussion of Background Information

Tabs which are also called Stay on Tabs, e.g., SOT, are attached tosheet metal lids and are known devices for opening beverage cans, so aconsumer can gain access to a liquid within the beverage can. When thetab is in an attached condition to the sheet metal lid of the beveragecan the tab provides for a consumer to open an openable area in thesurface of a lid (usually designated as “panel”). For example, the tabis taken at a grip end of the tab and raised with a vertical tiltingmotion, so as to break open the openable area of the lid along a line ofweakness (usually called score line).

Particularly when large opening ends (LOEs) are used for the openablearea, difficulties are encountered in the related art when arranging thepositioning of the tab along the line of weakness (or score line), whenthe tab is in an attached condition to the sheet metal lid. U.S. Pat.No. 5,799,816 (Schubert) attempts to deal with the above problem, byarranging an attaching portion (or “rivet island”) of the tab to besecured to the panel of the sheet metal lid through a shaped rivet. Theshaped rivet provides for an anti-rotation feature which maintainsproper alignment of the tab and particularly its nose portion, so as tominimize failed openings. See FIGS. 2 and 4 and Col. 3, lines 63-67 andCol. 5, lines 37-44 of Schubert.

The instant invention addresses the technical problems related to thepositional alignment of the tab in the attached condition, as well asthe manufacture and reliability of the anti-rotation block.

SUMMARY OF THE INVENTION

The present invention improves the positional alignment of a tab in anattached condition arranged on a panel, as well as improve themanufacture and reliability of the anti-rotation block.

According to one feature of the invention, a sheet metal lid can be usedfor closing a can body. The lid may include a panel portion and aseamable edge that surrounds the panel, so the edge can be adapted forattaching to the can body. An openable area defined on the panelincludes a weakening line, wherein a tab can be disposed on a mountingplace outside of the openable area. The tab embodied according to theinvention may include a grip portion, an opening portion, and anattaching portion. The attaching portion can be provided for attachingthe tab substantially parallel with respect to the panel, such that thetab as attached is disposed with its opening portion above the openablearea. Further, near the at least one edge of the attaching portion, atleast on strip-shaped projection can be shaped to protrude out of thepanel for a limiting pivoting movement (α) of the tab around themounting place.

According to another feature of the invention, the projection need notprotrude through an opening in the attaching portion, and the attachingportion does not need to be provided with an opening for the abovepurpose. Instead, the attaching portion can be kept whole, and ablocking element is provided to act on the attaching portion from anoutside arrangement.

In order to obtain the blocking effect, which may also be a limitingeffect, —or to completely prevent a rotating movement of the tab up to asubstantial limit of the rotating movement, an outer edge of the flatattaching portion (rivet island) abuts against the projection that isshaped to protrude out of the sheet metal lid. Since the projection haspositional stability on the panel in all operating positions, even whenstarting to break open the openable area, and since the attachingportion is substantially coplanar with the panel of the lid, tightlysurrounding the central rivet as a mounting place, none of the aboveelements provided for preventing rotation operationally moves apart withan opening movement of the tab. Since the opening movement is a verticaltilting motion, anti-rotation is unaffected due to an outer edge of theattaching portion abutting on the panel projection.

Advantageously, a peripheral edge on a known tab within the art may alsobe used, since the edge does not have to be specifically arranged forobtaining the rotation barrier effect after the attachment of the tab tothe panel (“staking”). The only manipulation is effected on the sheetmetal lid itself, which is provided with a shape, as is the rivet in apreliminary phase, which shape may preferably also be pre-formedtogether with the formation of the rivet and modified in shape, or moreprecisely “reformed” subsequently, in a further processing step of thesheet metal lid being manufactured. The projection may thus be formedintegrally with the sheet metal lid, as is the mounting place byone-piece manufacturing for the attaching portion of the tab.

The projection may have a strip shape (or line shape) alignedtransversely and/or parallel to a longitudinal extension of the tab(e.g., longitudinal axis or longitudinal plane), engaging at acorrespondingly aligned peripheral edge of the attaching portion for itsblocking effect. In a longitudinal extension, the projection may extendover more than 30%, 50%, or possibly to more than 80% of the width ofthe attaching portion.

If the projections extend parallel to the longitudinal extension of thetab, or perpendicular to the transverse direction mentioned above, thanthe longitudinal extension may be shorter than the longitudinalextension of the attaching portion (rivet island) of the tab. Further,the projection may be at a position as distant as possible from themounting place, such that at least one portion of the two peripherallines mentioned above, abuts and prevents rotation on the at least oneprojection when starting a rotating movement.

Arranging the attachment portion as distant as possible from themounting place allows the greatest possible force to be exerted, whichprovides a blocking effect to prevent rotation of the tab by a user. Inparticular, the projections oriented parallel to the longitudinalextension of the tab allows for a great force to be applied for thelocking effect. All three of the above structural arrangements may beused either singularly or used in a combination.

The height or vertical extension of the at least one projection, may beat least equal to or possibly greater than the thickness of the sheetmetal of the attaching portion, in order to obtain a reliable fixingposition. Further, the above arrangement does not impair the operatingor raising the grip portion, since the attaching portion is reliablysituated on the other side of the mounting place and coplanar with thepanel section surrounding the rivet (button coin area).

Several projections may be provided, but not all projections have to beassigned to the same outer edge portion of the attaching portion. Theprojections may also be differently embodied, i.e. strip-shaped, roundto oval, or a combination thereof. If a line-shaped outer edge portionof the attaching portion is provided, a line-shaped (strip-shaped)embodiment of the projections may be advantageous. The line-shaped stripdesign may also be achieved by arranging at least two punctiformprojections in line, which then form a group that is assigned to thesame outer edge portion of the attaching portion.

The attaching portion in the form of a mounting tongue can be connectedto the rest of the tab via a buckling portion in the form of anarticulation line, i.e. integrally. It is thus provided between theopening portion (the rupture nose) and the grip portion which can beprovided with a hole.

If the attaching portion is substantially rectangular, the substantiallyrectangular, flat, attaching portion can be formed by using thearticulation line and three edge lines. Particularly, the flat orsurface portion can be square in shape, and the rivet head positionedcloser to the articulation line, so as not to be centrally arrangedafter mounting. The distance of the outwardly directing peripheral edgecan therefore be larger than half the longitudinal extension of theattaching portion, so that a correspondingly improved force effect isachieved when a projection on the panel can be assigned to theperipheral edge farthest from the mounting place.

Further, it is possible for at least one of the projections to have anasymmetrical cross section, so as to have a steeper flank facing theattaching portion than the flank facing away from the attaching portion.The above configuration may also be selected for example, for thepunctiform or oval projections.

According to another feature of the invention, a subsequent reshaping,reforming, or post-forming may include the reduction of the thickness ofa top side of the (strip-shaped) projection, thus, achieving thesolidification of the portion together with the projection as a whole.The score line may also be applied simultaneously with the reforming asmentioned above.

The result of reforming can be visually apparent in a flattened topside. Thus, the projection mentioned above can have a larger width thanits total height. Further, the respective longitudinal extension of aprojection can be considerably larger than the width of the projection.This can apply to elongated strip-shaped or line-shaped projections.When a steeper flank portion is formed it can be more pronounced thanthe preform. Further, a peripheral edge may be obtained having (atleast) one portion extending at an angle substantially 90° relative tothe plane of the panel. This applies to the edge opposing the assignedperipheral edge portion of the attaching portion. An embossing processalso helps to give a stronger or steeper shape to the flank, theembossing provides for the reinforcement of the reformed sheet metal onthe top side.

Further, if several projections are provided they do not have to engagethe same edge line of the attaching portion at the start of a rotatingmovement, but instead may be assigned to different outer edges.

A still unfinished sheet metal lid is prepared to receive a tab includesthe formation of the projection that is sufficiently positioned to bedistant from the intended mounting place (from the re-formed rivet orits preform). Further, at such a distance the outer edge in the form ofan edge of the attaching surface (rivet island) facing away from thefuture rivet can be located very close to the projection, therebyachieving the rotation stopping effect. Furthermore, since the locationis in the outer edge portion of a rivet head zone or the “rivet base”,it can extend visibly around the formation of the rivet center remainingfrom the rivet perform.

The projection arranged as a line or strip can be positioned at leastpartially outside the weakened rivet base portion, in which the sheetmetal may be thin due to the shaping of the mounting place. The abovearrangement can address a peripheral portion of the rivet base zonewhich may be more than 40% of an assumed surface of a strip-shapedprojection lying outside the rivet base zone.

The rivet base zone can be arranged to visibly change the surfaceremaining on the inside of the sheet metal lid after the rivet has beenformed and the tab has been mounted. Since the projection is placed inthe outer portion, i.e. as distant as possible from the weakened sheetmetal or the thin sheet metal, the re-formed portion may be considerablyhigher before the sheet metal is damaged. Further, the re-forming mayachieve heights that can be above a sheet metal thickness of theattaching portion of the tab.

The projection may be provided with a strip shape, as well as bedesigned to have a length longer than the diameter of the finished rivethead.

The attaching portion can be formed from a piece of the central portionof the tab, in which only minor gaps are visible between the attachingportion, which is displaced downwards to a lower plane by a doublebuckling line, and the parallel plane of the rest of the tab, which maybe somewhat higher. Accordingly, the mounting of the projections on atleast one of the free peripheral edges facing outward from the attachingportion may be barely visible from the outside, so that the rotationblocking is virtually invisible to the observer. A colored tab does notnecessarily have to change in a colored shape.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described in the detailed descriptionwhich follows, in which like reference numerals represent similar partsthroughout the several views of the drawings, and wherein:

FIG. 1 shows the first stage of three stages in a manufacturing processof a sheet metal lid, which introduces, in part, a score line orweakening line, U-shaped bead and mounting place;

FIG. 2 shows the second stage of three stages in a manufacturing processof a sheet metal lid, which introduces, in part, beads along the tab,finger depression and an eyeball shaped bead;

FIG. 3 shows the third stage of three stages in a manufacturing processof a sheet metal lid, which introduces, in part, an attaching tongue,tab, buckling line and open position;

FIG. 4 is an enlarged section from FIG. 3, particularly showing theattaching portion 31 and the rivet 11 as mounting place;

FIG. 4 a is a cross section along line C-C in FIG. 4;

FIG. 5 is an alternative configuration for the positional fixing ofattaching portion 31 and thus of the entire tab 30;

FIG. 5 a is a sectional view through the center plane of FIG. 5,alternatively through the vertical longitudinal plane 100 of FIG. 3;

FIG. 6 is an alternative arrangement of projections for blockingrotation of the tab;

FIG. 7 is another alternative arrangement to FIG. 6;

FIG. 8 is a cross section along a longitudinal plane 100, to illustratea sharp front edge 20 a of a strip-shaped or line-shaped projection 20;

FIG. 8 a is a cross section of an embodiment of the inventioncorresponding to the illustration in FIG. 8;

FIG. 9 a is a schematic explanation of the effective torques in aprojection extending parallel to the center plane 100;

FIG. 9 b is a comparable explanation of the effective torques in aprojection 20 located transversely to the center plane 100; and

FIG. 10 is an illustration of a portion 11 a around a rivet 11, theportion being visible from the inside of the lid, a projection 20 beingvisible as an outwardly vaulted cavity. This figure identifies only asection around a rivet 11 as a mounting place.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

FIGS. 1 to 3 show a sheet metal lid having a visible edge portion 12suitable for seaming to a body of a beverage can. The sheet metal lidcan be produced from thin sheet metal, typically less than 0.24 mm,which may have already passed through previous workstations beforereaching the stage shown in FIG. 1. Further, the lid may include aninner surface portion or panel 10 that can be surrounded by a seamableedge 12. Further, within the panel 10, a weakening line 16 can beprovided around an openable area, wherein the openable area may besurrounded by a substantially U-shaped bead 18. The bead opens towardsthe center portion of the panel, wherein the substantially O-shapedweakening line 16 is designed as a score line. A transitional sectionthat is not scored serves as a connecting portion to the rest of panel10, when the openable area 17 is broken in and along the score line 16by the effect of a tab.

A mounting place 11 is positioned approximately in the middle of thepanel. An attaching portion 31 or a sheet metal tongue can be part ofthe tab (FIG. 3), which can be integrally formed via an articulationline or a buckling line 38. The tab 30 can include a grip portion 32that may be arranged with a circular opening, so the tab 30 can beoperated by the user for breaking open the score line 16. See FIG. 1.The tab 30 may also include an opening portion 33 arranged before theattaching portion 31, wherein the opening portion may be located as arupture nose above the openable area 17. Further, an additionaleyeball-shaped bead 18 a (FIG. 2) can be provided to reinforce thetransverse LOE (large opening ends) openable area, resulting in anarrangement in which the applied forces from the opening forces are ableto rupture the starting portion or arcuate end of the score line 16. Themounted tab 30 may be substantially parallel to the panel, so as to beslightly bulged or not exactly arranged in one place, through an areaaround the mounting place 11. Further, the mounting place 11 can besubstantially planar so as to allow for a substantially parallelarrangement of the attaching tongue of the tab 30.

FIGS. 1, 3 and 5 show the longitudinal midplane 100 extending in adirection to the longitudinal extension of the tab 30, as well as atransverse plane 101 (FIG. 5) extending perpendicularly thereto.

The grip portion 32 (of an attached or staked end) of the tab 30overlaps a finger depression 13, which is provided in the panel 10, atapproximately the same distance as the inner reinforcing bead 18 a onthe other side of mounting place 11. The tab 30 may only be attached(FIG. 3) during the manufacture of the finished sheet metal lid. Priorto the completion of manufacture of finished sheet metal lid, themounting place 11 may initially be formed as a bubble to permit theattaching portion 31 of the tab 30 to be attached to the panel 10. FIG.1 shows three strip-shaped projections 20, 21 re-formed as upwardlyprotruding beads (i.e. towards the outside of the sheet metal lid)around said mounting place 11. The bead 20 can extend transversely tothe midplane 100 which may be longer than the two neighboring beads thatcan extend parallel to the midplane 100. FIG. 4 shows detailed view via21 a, 21 b of a possible arrangement of the longer bead 20 with respectto the attaching tongue 31.

FIG. 1 shows the attachment tongue 31 and the distances of the beads 20,21 from the mounting place 11. At a particular manufacturing station,the re-forming of the three beads 20, 21 a, 21 b results in a formationof the beads (or projections). See FIG. 3. At the above manufacturingstation, the projections are re-formed integrally from the sheet metallid or panel 10 so as to extend in a vertical direction at least to aheight h that is equal to the sheet metal thickness of the attachingportion 31 of the tab 30. Further, the projections are then providedwith correct profile geometries.

FIG. 3 shows the rivet head in a forming process with a larger diameterthan is shown in FIGS. 1 and 2, wherein the tab 30 is placed over therivet shaft. While the rivet head is forming, the tab 30 is attached tothe panel 10 via the attaching portion 31, wherein the attaching portion31 can be connected to the rest of the tab 30 through a buckling line38. The opening section 33 can be located above the openable area 17inside the score line 16, close to an additional stiffening bead 18 a.

In order to ensure the rupture force and the accuracy in thebreaking-open process, the tab 30 rotational movement direction isdesignated by α in FIG. 4.

To open the opening area 17, the front nose end of the opening portion33 is moved away from an exact position to provide a rupture force,resulting in continued tearing until the subsequent complete opening ofthe opening area 17. It is obvious that the front nose end of theopening portion 33 would be moved away from the exact position that isprovided to ensure the rupture force, the continued tearing and thesubsequent complete opening of the opening area 17.—FIG. 4 shows the tabrotational movement α being as minimal as possible, or possiblyrestricting all rotational movement. FIGS. 4-6 show the threestrip-shaped projections 21 a, 21 b and 20 being assigned to the threefree peripheral edges 31 a, 31 b, 31 c of the attaching portion 31 ofthe grip portion 30. A small gap 21′, 21″ and 20′ may be left betweeneach outwardly facing edge and the respective inner edge of the eachprojection, for example, 31 c from 20″ at the projection 20. However,the gap may also be reduced to zero on at least one of the outwardlyfacing edges of said attaching portion 31.

FIG. 4 shows the width of the attaching portion 31 being marked with“b”, and the two projections 21 b, 21 a (or beads) positioned parallelto the longitudinal midplane 100 and at a distance from the attachingportion 31 via inside edges 21 b′ and 21 a′. The longitudinal extensionof the attaching portion 31 in the plane 100 extends over the rivet headas the mounting place 11. The length of the two beads 21 a, 21 b can beshorter than half the longitudinal extension of the attaching portion31. Further, beads may be positioned as far as possible to the rear areaof the attaching portion in order to apply the greatest possible forcefor the locking effect or positional fixing with an assumed rotationmovement α.

The above arrangmement of the locking effect (or positional fixing) withthe assumed rotation movement α, may further be effected with thegreatest possible distance of the projection 20 disposed in thetransverse plane 101, which is transverse to the longitudinal mid-plane100. Further, the projection 20 may be longer than two projections 21 b,21 a (or beads) positioned parallel to the longitudinal midplane 100. Itis possible for the projection 20 to extend over more than half or evenmore than 80% of the width b of the attaching portion 31.

According to another feature of the invention, it is also possible forone or more of the three strip-shaped projections or beads describedabove to be omitted from the attaching portion 31.

According to another embodiment of the invention, the attaching portion31 may be arranged with one projection 20, as viewed in FIG. 5. Further,the outwardly facing edge 31 c is positioned farthest from the rivet ormounting place 11 and approximate the strip-shaped projection (orgeometry) 20, so as to minimize or even prevent the rotational movementα of the tab 30. It is possible to limit the rotational movement α ofthe tab 30 with the positioning of the projection 20 to such an extentthat the opening behavior of the tab is not affected when the tab 30 istilted upwards at the grip portion 32. The rotating movement α can bepredetermined by at least two limit values, which are defined by theabutment in an assumed rotation α (in both directions about the axis ofthe rivet 11), resulting in limited or even possibly no rotatingmovement α. Further, the rotational or pivoting movement α issubstantially in the plane in which the panel is disposed in an areasurrounding the rivet head 11, such that the plane is kept parallel bythe plane of the attaching portion 31 (which may have a planar orsurface extension). The attaching portion 31 may be embodied as arectangle or square, having two parallel peripheral edges or edges 31 b,31 a and one peripheral edge 31 c at a distance from the articulationline 38 and extending parallel thereto. Another embodiment may includethe attaching portion 31 having an arcuate form similar to a triangularshape, or a more distant shape which may not have a straight extendingperipheral edge 31 c.

The cross-section shown in FIG. 4 a relates to the correspondingsectional line of FIG. 4. According thereto, an asymmetrical design ofthe strip-shaped projections 21 a, 21 b is provided, a steeper flank 21b′ being located closer to a peripheral edge 31 b than the less steepflank 21 b″ of strip-shaped projection 21 b. The same is valid for theparallel projection 21 a and its associated peripheral edge 31 a.

In FIG. 4 a, the sheet metal lid in the panel 10 and the attachingportion 31 are parallel, with the rivet 11 (not shown). An assumedrotation movement causes the peripheral edge 31 a to abut on the steeperflank of the projection 21 a, or the peripheral edge 31 b to abut on thesteeper flank 21 b′ of the projection 21 b. A narrower association ofthe steeper flanks, due to their almost vertically extending ridges orsteps, permits any minor (residual) rotating movement in the plane ofthe sheet metal lid of the panel 10 in the rivet zone 11 to be almostcompletely prevented.

FIG. 5 a shows a cross section relating to FIG. 5 and arranged throughthe longitudinal plane 100. FIG. 5 a shows one projection 20 cooperatingwith the peripheral edge 31 c of the attaching portion 31 to preventfunction-affecting rotational movements α. Further, the rivet headdesigned as a mounting place 11 is visible through an opening in theattaching portion 31. Also visible is the allocation of the freeperipheral edge 31 c to the projection 20 re-formed from the metal sheetlid, which projection 20 (see FIG. 4 a) indicates that other projections21 b, 21 a may also have an asymmetrical shape.

FIG. 8 shows the asymmetry in a transverse direction to the longitudinalextension of the projection 20 (in the longitudinal plane 100 of the lidor the tab). Further, the projection 20 can be associated to theperipheral edge 31 c of the attaching portion 31. By a double formingprocess, a first pre-forming according to FIG. 1 and a second re-formingaccording to FIG. 2, resulting in a very steep front edge 20″ or 20 acan be obtained, having a very large height h (relative to the thicknessof the sheet metal). Furthermore, the projection 20 is arranged asdistant as possible from the sensitive area of the rivet base 11 a, incase the sheet lid is damaged which would resulting in damage to theprojection 20. The steep front edge 20 a (or 20″ according to FIG. 4),together with a less steeply extending second flank 20 b, which providesno blocking effect with the attaching portion 31, allows higher forcesto be applied. Further, the attaching portion 31 is less likely to bedeformed upwards (perpendicularly to the plane of panel 10) on a moreflatly extending peripheral edge and to thereby lose the blockingeffect.

FIG. 8 a shows the cross section extending in a longitudinal direction,as determined by the longitudinal midplane 100 for FIG. 4, 5, 8 asviewed in the bottom section. Further, the top illustration shows apreform 20*, in a two-stage manufacturing process prior to the secondstep (post-forming or re-forming). In a first shaping step, for exampleaccording to FIG. 1, a pre-form 20*, which may have a rampart (orridge-shaped structure), can be shaped to protrude out of a panel 10with two flat inclines and a middle portion extremely rounded. In asecond re-forming step, (see FIG. 2), a much steeper front edge 20″ (seeFIG. 4) or 20 a (see FIG. 8) is obtained, while the sheet metal lidnevertheless remains undamaged. The second re-forming and the resultafter attaching the grip portion are shown in the lower illustration ofFIG. 8 a. It is understood that in both the upper and the lowerillustrations, the strip-shaped projection 20 can extend perpendicularlyto the paper plane, in a transverse plane 101 extending perpendicularlyto the longitudinal midplane 100. The transverse plane 101 is a relativeindication referring to the position of the pre-form 20*, in which thereis a symmetry of the pre-form initially shaped from the sheet metal lidrelative to the plane 101, that is abandoned during re-forming, as isillustrated by the finished projection 20 in the bottom representation,in which it is no longer symmetrical to the transverse plane 101.

The following embodiments refer to the bottom illustration of FIG. 8 a.The rivet 11 used for attaching portion 31 to the sheet metal lid 10 canbe located to the left (not shown). A rear end 31 c of an attachingportion 31 is the peripheral edge that is assigned to a front edge 20″of a projection 20, possibly leaving a narrow gap 20′ (see FIG. 4). Theprojection 20 is characterized by an asymmetry, with a steep front edge20″ (or 20 a) and a less steeply extending peripheral edge 20 b facingoutwards. As a result of re-forming, the projection may also have aplateau-shaped top side 20 c, providing for the projection 20 to reach avery large height h relative to the thickness of the sheet metal,despite the relatively flat appearance of its shape. However, the widthof the projection is arranged to have an increased strength with thewidth being larger than its height h, particularly about twice as wideas it is high, so that the essential portion of the projection 20 can besituated to the right of the transverse plane 101.

The re-forming step includes shaping the pre-form 20* with a coining (oran embossing operation) for flattening the top surface 20 c. In there-forming process, a tool is applied from the top and from the bottomfor re-forming. The slight bend that is detectable on the left in therising flank of the pre-form 20′ may be recognized in the bottom finalform via the sharp front edge 20″ being introduced in the initiallygently rising front incline of the shaped rampart 20*. To the right ofthe transverse plane 101, the second incline of the rampart is formedfrom bottom to top, for forming a flat shape 20 c, startingapproximately at the instep of said rampart 20* and leading gently overto the rest of the sheet metal panel 10 in portion 20 b.

Additionally, in the final form, the attaching portion 31 and the tab 30are already attached according to FIG. 3. The tab can be arranged withits intermediate web between the left opening and the grip opening 32 bsubstantially above the transversely extending projection 20. The twoopenings of the tab are shown in figure 3, one opening resulting fromthe formation of the attaching portion 31, which is further connected tothe tab 30 via an articulation line 38, whereas the opening forinserting a finger is designed particularly. The opening 32 b is a partof the grip portion 32, the web 32 a between said two openings beingshown slightly bulged in FIG. 8 a, having a front edge 32 c that wasrelated to the free edge 31 c of the attaching portion 31 duringmanufacture. A major part of the projection 20 is thus located belowsaid web and is barely visible from outside.

In this context, a modified sequence of the two-stage re-forming may beperformed besides the processing sequence according to FIGS. 1 to 3. Forexample, the initial introduction of the pre-forms, as illustrated bythe pre-form 20* in the top picture of FIG. 8 a, in a first workingstep, shown without the introduction of score lines (as weakening lines16). In this case multiple projections can be used to block rotatingmovements which may include all the pre-forms being shaped. The firstscore line introduced can be jointly in a single working step, in whichthe re-forming (further shaping) of the pre-formed projections takesplace. In this step, the projections receive their correct, assignedprofile, as is shown in the bottom illustration of FIG. 8 a. Forexample, this profile is capable of being transferred not only to thetransversely extending projection 20, but also to the other projections,provided that they have been shaped as pre-forms in the previousoperation. In this way, a scoring operation, which subjects the sheetmetal to severe stress, is not performed at the same time as the shapingof the pre-form takes place in the first operation, since the shapingprocess causes considerable stress to the sheet metal lid. The scoreline may be introduced simultaneously with the re-forming operation.During re-forming (see FIG. 8 a), the wall thickness on the top side ofthe projection is reduced by about 10% to 15%, with simultaneouscompression and solidification of the same portion, thus achievinguniformity from top to bottom by the embossing operation (or coining).

FIG. 6 shows an attachment of two substantially punctiform projections23 a, 23 b to the longitudinal sides 31 a, 31 b of the attaching portion31. Additionally, a projection 22 may be provided on transverse edge 31c of the attaching portion 31, wherein the projection 22 may beelongated (such as oval shape) and or substantially circular shape.

FIG. 7 shows a group of projections arranged to a single outer edge(outwardly facing peripheral line) of the attaching portion 31. Thegroup 24 may include three individual, substantially punctiformprojections assigned to the peripheral edge 31 c, but may as well beassigned to the two other peripheral edges 31 a and 31 b. Also, only twopunctiform projections can be used in FIG. 7. In the same way, theasymmetrical shape of the projections formed to protrude in upwarddirection in accordance with FIG. 4 a, or also FIG. 5 a or 8 a, may alsobe applied to the above mentioned embodiments.

For example, one projection may be used with a peripheral edge 31 cextending transversely to the longitudinal plane 100 of the tab 30,wherein the rotational movement in both directions can be prevented ifthe projection extends at least on both sides of the midplane. On theother hand, if a projection is arranged on a peripheral edge extendingparallel to the longitudinal plane 100, then at least two projectionsshould be provided on the two correspondingly available edges as “stopedges”, for symmetrically limiting rotational movements of the tab 30.

All the projections described may be arranged outside the attachingportion 30, in order to be able to cooperate in a blocking manner withat least one of its respective outer peripheral edges (edge).

FIGS. 9 a and 9 b show a top view of the attaching portion 31 disposedon the panel 10 over a mounting place 11 (or rivet head). A lateralprojection 21 a extends parallel to the midplane 100 of the tab 30, uponwhich a force is exerted on the projection due to an assumed rotationmovement in a direction α. An assumed length I of the attaching portion31 to the mounting place 11 can be located closer to the articulationline 38 than to the rear end 31 c of the attaching portion 31, so thatan effective power arm I₁ is larger than half of the length I of theattaching portion 31. Because of the positioning of the line orstrip-shaped projection 21 a that is close to the rear edge line 31 c, aforce via a large lever arm can apply a large torque for blocking(blocking moment) an undesired rotation.

Similarly, the exertion of torques may be explained in a projection 20that extends perpendicularly to a midplane 100, wherein the projectioncan substantially occupy the entire width b of the attaching portion 31near to a rear edge line 31 c thereof. In this case, the (maximum) powerarm is designated b1, and in a first approximation, the lever arm isapproximately (but not exactly) equal to half of the width b, marked aslever arm b₁ in an assumed (hypothetical) rotational movement in adirection α as illustrated. The corresponding force via the lever arm b1is applied by the projection 20, or the front edge 20 a thereof (edge20″ in FIG. 4). The corner of the attaching portion 31 being slightlyrounded, the entire half of the width is not available for use as alever arm, but instead between 70% and 100% of b/2, substantially in therange of between 80% and 90%.

FIG. 10 shows a thinned zone of the sheet metal lid around a rivet head11 said zone being visible from the inside. Said rivet base zone 11 a isa zone that remains on an outer side after the second re-forming of therivet head 11, usually visibly by circular lines surrounding the centerof the rivet as mounting place 11.

The “button coin area” most likely cannot withstand strong stresses,since the sheet metal is reduced in thickness due to the rivet beingshaped to protrude in an outward direction. Projection 20 occupies asurface area f₂₀ that is line or strip-shaped mounted in the outer edgezone 11 b of the rivet base, or rather displaced far outside of the thinsheet metal zone susceptible to possible damage. The attaching portion31 is marked by a dashed line showing the relative position of the “coinarea”. Alternatively or cumulatively, the projection 20 can be shown aslocated at the rear edge 31 c, where the two lateral projections 21 a,21 b may also be provided. Which can result in the projections beingpositioned close to the peripheral zone of the rivet base and notdisplaced to the thinned out portion near the rivet head, which portionis susceptible to damages.

For example, a more precise dimensioning of the surface areas may showthe strip-shaped projection 20 situated at least partly outside therivet base zone (or coin area) and outside the outer peripheral portion11 b thereof. The outward displacement can be equal to at least 40% ofthe surface portion f₂₀, which is no longer in the periphery 11 b of therivet base 11 a, but outside thereof. This position and the position andextension of the coin area can easily be visible from the inside of thesheet metal lid.

1-53. (canceled)
 54. A sheet metal lid for closing a can body, the lidcomprising: a panel having a weakening line defining an openable area; aseamable edge, surrounding the panel, being attachable to the body; atab including a grip portion, an opening portion and an attachingportion, such that the attaching portion is arranged for attaching thetab substantially parallel with respect to the panel; a mounting placepositioned outside the openable area, such that the tab is arranged onthe mounting place; at least one strip-shaped projection shaped toprotrude out of the panel for limiting or blocking a pivoting movementof the tab around the mounting place; wherein the opening portion isarranged above the openable area, and at least one edge of the attachingportion being proximate the at least one strip-shaped projection.
 55. Asheet metal lid for closing a can body, the lid comprising: a panelhaving a weakening line defining an openable area; a seamable edge,surrounding the panel, being attachable to the body; a tab including agrip portion, an opening portion and an attaching portion, such that theattaching portion is arranged for attaching the tab substantiallyparallel with respect to the panel; a mounting place positioned outsidethe openable area, such that the tab is arranged on the mounting place,and the opening portion is arranged above the openable area; the panelcomprising at least one strip-shaped projection being arranged outsidethe attaching portion to block a substantial pivoting movement of thetab in a plane parallel to the panel.
 56. A sheet metal lid for closinga can body, the lid comprising: a panel having a weakening line definingan openable area; a seamable edge, surrounding the panel, beingattachable to the body; a tab including a grip portion, an openingportion and an attaching portion, such that the attaching portion isarranged for attaching the tab substantially parallel with respect tothe panel, and includes a surface or planar extension smaller than anextension of the tab; a mounting place positioned outside the openablearea, such that the tab is arranged on the mounting place, and theopening portion is positioned above the openable area; and the attachingportion comprising at least one blocking element arranged outside theextension of the attaching portion for delimiting a pivoting movement ofthe tab.
 57. A sheet metal lid for closing a can body, the lidcomprising: a panel having a weakening line defining an openable area; aseamable edge, surrounding the panel, being attachable to the body; atab including a grip portion, an opening portion and an attachingportion, such that the attaching portion is arranged for attaching thetab substantially parallel with respect to the panel; a mounting placepositioned outside the openable area, such that the tab is arranged onthe mounting place; the panel comprising at least projection forlimiting or blocking a pivoting movement of the tab by contacting atleast one outer edge of the attaching portion.
 58. The lid in accordancewith claim 57, wherein the at least one projection extends over at least30% of a width or a length of the attaching portion.
 59. The lid inaccordance with claim 57, wherein the at least one projection extendsover at least 50% of a width or a length of the attaching portion. 60.The lid in accordance with claim 57, wherein a plurality of projectionsare provided near the at least one edge of the attaching portion. 61.The lid in accordance with claim 60, wherein at least one of theplurality of projections has a line or strip shape.
 62. The lid inaccordance with claim 60, wherein at least one of the plurality ofprojections has an approximate round to oval shape.
 63. The lid inaccordance with claim 61, wherein at least two of the projections arenot equally aligned.
 64. The lid in accordance with claim 57, whereinthe limiting or blocking of the pivoting movement of the tab occursthrough contact with the at least one projection.
 65. The lid inaccordance with claim 57, wherein the at least one projection isarranged between the grip portion and the opening portion of the tab onthe panel.
 66. The lid in accordance with claim 57, wherein theattaching portion is substantially rectangular in shape and having atleast three outer edge portions.
 67. The lid in accordance with claim57, wherein the attaching portion is substantially square in shape andhaving at least three outer edge portions.
 68. The lid in accordancewith claim 57, wherein the attaching portion is connected to anarticulation line on the tab, so that the opening portion is tiltable ina substantially vertically direction to a plane of the panel whenactuating the grip portion.
 69. The lid in accordance with claim 68,wherein the tilting movement causes an opening of the openable areaalong the weakening line.
 70. The lid in accordance with claim 57,wherein the limiting or blocking of the pivoting movement of the tab ismaintained throughout the entire vertical tilting of the tab.
 71. Thelid in accordance with claim 60, wherein the plurality of projectionsare arranged such that when horizontally pivoting the tab, each of theplurality of projections engages a single edge of the at least one edgeof the attaching portion.
 72. The lid in accordance with claim 57,wherein the at least one projection has a cross section which is shapedasymmetrically in a direction transverse to its longitudinal extension.73. The lid in accordance with claim 72, wherein the asymmetrical shapeincludes variable steep flanks or sides that are non parallel to eachother, or the asymmetrical shape includes a second steep flank that isless steep than first steep flank so as not to extend parallel to eachother.
 74. The lid in accordance with claim 73, wherein the first steepflank is located closer to an outer edge portion of the attachingportion than the second steep flank of the same projection.
 75. The lidin accordance with claim 54, wherein the at least one projection has aheight greater than 300 μm, measured from a top side facing outwards ofthe panel around the projection.
 76. The lid in accordance with claim75, wherein the height is substantially adapted to a height or thicknessof a sheet metal of the attaching portion for the limiting or blockingof the pivoting movement of the attaching portion.
 77. The lid inaccordance with claim 76, wherein the height of the at least oneprojection is not less than substantially the thickness of the sheetmetal at the respective outer edge portion of the attaching portion. 78.The lid in accordance with claim 54, wherein the at least one projectionis shaped by an initial shaping or pre-forming from the panel and isstructured and arranged in a final shape by a reshaping or reforming, sothat a reduction in the thickness of a top side of the projection iseffected during reforming.
 79. The lid in accordance with claim 78,wherein a first flank is shaped more steeply than a second flank of theprojection in a reforming process.
 80. The lid in accordance with claim54, wherein the at least one projection is located in a peripheral areaof a rivet base zone in the lid, such that the rivet base zone isvisible from an inside or a product side.
 81. The lid in accordance withclaim 80, wherein a part of the projection is located outside the rivetbase zone.
 82. The lid in accordance with claim 81, wherein more than40% of a surface area of the at least one projection is located outsidethe rivet base zone.
 83. The lid in accordance with claim 81, whereinthe rivet base zone extends as a mounting place annularly about a rivet,which is visible from the inside or the product side.
 84. The lid inaccordance with claim 80, wherein the at least one projection ispositioned as a secant to a tangent as a strip or a line in a edgeportion of the rivet base zone.
 85. A sheet metal lid for attaching atab having an attaching portion and for closing a can body, the lidcomprising: a tab including an attaching portion attached to the lid forclosing a body; at least one panel surrounded by a seamable edgeattachable to the body; an opening area being defined by a weakeningline on the at least one panel; the at least one panel comprising amounting place on which the tab is attachable; and at least oneprojection shaped to protrude from the at least one panel beingstructured and arranged to at least limit or block a pivoting movementof the tab through contact with at least one outer edge portion of theattaching portion.
 86. A sheet metal lid for attaching a tab with anattaching portion and for substantially closing a can body, the lidcomprising: at least one panel surrounded by a seamable edge that isattachable to the body; a weakening line defining an opening area on theat least one panel; the tab is attachable on a mounting place formed onthe at least one panel; at least one projection arranged near butremoved from the mounting place by a distance corresponding to at leastto a distance of an outer edge of the attaching portion of the tab fromthe mounting place, after mounting the attaching portion.
 87. The lid inaccordance with claim 86, wherein the outer edge is an edge line facingaway from the attaching portion, and wherein at least two edge lineslimit a surface extension of the attaching portion.
 88. The lid inaccordance with claim 86, wherein said at least two edge line portionshave a substantially straight-lined extension.
 89. A method for shapingthe sheet metal lid in accordance with claim 86, comprising: (A) shapinga pre-form of the projection out of the panel such that the pre-form islocated near the attaching portion of the tab, but at a distance fromthe mounting place; and (B) re-forming a front edge of the at least oneprojection, for obtaining a better blocking for an associated outer edgeportion of the attaching portion.
 90. The lid in accordance with claim89, shaping the pre-form of the at least one projection, followed by ascore line shaped into the at least one portion of the panel.
 91. Thelid in accordance with claim 90, re-forming includes an embossing bywhich a top side of the at least one projection is flattened andstiffened.
 92. The lid in accordance with claim 91, wherein the methodincludes a stiffening having a reduction of a sheet metal thickness byat least 10%.
 93. The lid in accordance with claim 57, wherein theprojection has the length of more than 80% of the width of the attachingportion.
 94. The lid in accordance with claim 54, wherein a plurality ofprojections are located near at least one portion of two or more edgesof the attaching portion.
 95. The lid in accordance with claim 60,wherein the at least one projection extends in a longitudinal directionof the tab and has a length that is not more than 50% of a longitudinalextension of the attaching portion, and in combination with a distanceof the outermost end of the at least one projection from a center of themounting place of the more than 50% of the longitudinal extension of theattaching portion.
 96. The lid in accordance with claim 60, wherein atleast three projections are arranged, two of which extendingsubstantially parallel to a longitudinal axis of the tab and oneextending substantially perpendicularly to the axis.
 97. A sheet metallid comprising: a panel portion coupled to an attachable tab through asubstantially flat attaching portion of the tab; a mounting element onwhich the tab is arranged; at least one projection extending upwardsfrom the panel portion which is structured and arranged with at leastone front stop edge for at least limiting or blocking a horizontalrotation movement of the tab.
 98. The lid in accordance with claim 97,wherein the mounting element is on a rivet integrally formed with thepanel portion.
 99. The lid in accordance with claim 97, wherein the atleast one front stop edge is linear.
 100. The lid in accordance withclaim 97, wherein the at least one front stop edge extends over morethan half of a width or at least 30% of a length of the flat attachingportion.
 101. The lid in accordance with claim 97, wherein the at leastone front stop edge is substantially perpendicular to a longitudinalplane extending along a length of the tab.
 102. The lid in accordancewith claim 97, wherein the at least one projection is formed by; (A)forming a front stop zone from a portion of the panel, and (B)re-shaping the stop zone into a shape which has a stop edge orre-shaping the stop zone into a shape which has the stop edge that issteeper or sharper than the stop zone shaped previously.
 103. The lid inaccordance with claim 97, wherein at least two stop edges are providedsubstantially parallel to a longitudinal plane extending along thelength of the tab.
 104. The lid in accordance with claim 98, wherein theat least one projection from the panel is shaped in an areacorresponding to a periphery of a rivet base portion or an embossedportion around the mounting place.
 105. The lid in accordance with claim97, wherein the at least one projection is flattened on a top sidethereof, and having a wall thickness being reduced thereof.
 106. The lidin accordance with claim 105, wherein the reduction is provided by anembossing operation.
 107. The lid in accordance with claim 105, whereina steeper edge of the at least one projection comprises at least oneportion extending at an angle of substantially 90° with respect to thepanel.
 108. The lid in accordance with claim 97, wherein the at leastone projection or the at least one stop edge has a greater width than aheight and a greater length than width.